The LFB later said the fire was in the restaurant's extraction system and tweeted: "We managed to confine the fire to the extraction system & limit damage. 6 staff left before we arrived, all uninjured."

The fire affected an area of the roof of nearby Indian restaurant The Delhi Brasserie near the junction with Old Compton Street.

A worker at nearby Ceviche restaurant, who only gave her name as Katie, said: "There was a lot of black smoke. It all happened very fast. It seemed to be coming from the roof and then the street flooded with black smoke.

"All the poor people from Ronnie Scott's had to run out in their party hats- they do Christmas lunches there at this time of year. But we weren't scared for our business, it was quite clear it was an isolated incident.

"It was certainly something you don't see every lunchtime. It was exciting for a few minutes. We were glad that we weren't affected and we were glad that Ronnie Scott's didn't burn down."

Lakhdar Melvena, a waitress at neighbouring restaurant Elcantara, said she was working in the basement when a worker from nearby Bar Italia alerted her to the fire.

She said: "I was in the basement getting some oranges and a woman came in and said the roof was on fire so I went straight outside and saw the smoke. I was worried that the fire was going to spread because the smoke coming in here was too much."